Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D263/00—Heterocyclic compounds containing 1,3-oxazole or hydrogenated 1,3-oxazole rings
  • C07D263/52—Heterocyclic compounds containing 1,3-oxazole or hydrogenated 1,3-oxazole rings condensed with carbocyclic rings or ring systems
  • C07D263/54—Benzoxazoles; Hydrogenated benzoxazoles
  • C07D263/58—Benzoxazoles; Hydrogenated benzoxazoles with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached in position 2

Definitions

• the present invention relates to the preparation of benzoxazolone from a phenol, and, to more especially, the preparation of benzoxazolone from chlorophenol.
• Benzoxazolone is a known compound having the structural formula: ##STR1## Such known compound is a useful intermediate in the synthesis of a variety of other materials, e.g., the insecticide phosalone. And benzoxazolone is ofttimes designated benzoxazolinone, in particular in the English speaking countries.
• a major object of the present invention is the provision of a simple and facile process for the preparation of benzoxazolone, starting with simple reactants and, more particularly, utilizing ortho-chlorophenol as the primary reactant.
• the present invention features a process for the preparation of benzoxazolone from ortho-chlorophenol, comprising, in a first step, heating a mixture of the ortho-chlorophenol and urea under positive ammonia pressure, and then, in a second distinct step, heating such reaction mixture resulting from said first step under atmospheric pressure, preferably in the presence of water.
• the first step of the subject process is carried out in the presence of a metal catalyst; a copper-based catalyst is advantageously employed for this purpose.
• a metal catalyst is advantageously employed for this purpose.
• exemplary of such catalysts are cuprous or cupric salts, in particular the halides, sulfates, phosphate, acetates, propionates and acetylacetonates (cuprous chloride is preferred), and also the oxides (in particular cuprous oxide), and copper metal; the catalysts comprising iron or nickel are also envisaged.
• the amount of catalyst present in the reaction medium is generally between 0.5 and 20%, preferably between 2 and 10%, by weight, relative to the ortho-chlorophenol. However, while amounts of catalyst without these ranges can indeed be used, such would not constitute any significant advantage, economic or otherwise.
• the first reaction step is also carried out under ammonia pressure.
• the subject process comprises heating a liquid reaction medium under a pressurized atmosphere which includes ammonia gas.
• the NH 3 is added, under pressure, to the atmosphere surmounting or enveloping the reaction medium, but it is also possible to effect formation of this atmosphere under ammonia pressure by permitting the urea for the reaction mixture to decompose.
• the total pressure is advantageously between 1 and 60 bars (relative pressures), preferably between 3 and 40 bars. Higher pressures, e.g., ranging up to 150 bars, can also be used, but this too does not afford a great economic advantage.
• the introduction of water into the reaction medium circumscribes another preferred embodiment of the invention, the effect of which, in particular, is to partially decompose the urea and thus to assist in formation of ammonia, and this can contribute to an increase in the ammonia pressure prevailing over the reaction medium.
• the proportion of water in the reaction medium is advantageously less than 20%, preferably less than 10% (percentages by weight, relative to the total reaction medium).
• the ammonia gas advantageously contributes a partial pressure of more than 50% of the total pressure, preferably of more than 90% of this pressure.
• Said ammonia gas is most frequently supplied from either an external feed, or is earlier introduced into the reactor, or results from decomposition of the urea, or from a combination of any two or more of the aforesaid factors.
• the molar ratio of the urea employed in the reaction medium, relative to the ortho-chlorophenol, is typically between 1 and 15, preferably between 1.2 and 8.
• the urea present in the reaction medium is optionally prepared, in situ, by reacting CO 2 with the ammonia.
• the temperature of the reaction medium in the first step is advantageously between 100° and 250° C., preferably between 140° and 230° C.
• the first reaction step can also be carried out in the presence of inert inorganic or organic solvents, but, generally, it is preferably carried out in bulk.
• Such bulk reaction mixture is typically liquid at the temperature of reaction, albeit it can indeed be non-liquid at ambient temperature.
• this first reaction step can obviously vary, depending upon the operating conditions. Simple routine experiments will enable those skilled in the art to determine the optimum duration; generally, this first reaction step is continued until the ortho-chlorophenol content of the reaction admixture is no longer varying to any significant extent, or, stated differently, until the degree of conversion of the ortho-chlorophenol has essentially reached its maximum, not taking into account simple thermal and/or chemical degradation.
• the process of the invention comprises two reaction steps; in fact, these two steps are separate and distinct, in particular by reason of the fact that the first is conducted under a pressure head, while the second is simply carried out under atmospheric pressure.
• these two steps are somewhat similar from a practical point of view and same can conveniently be carried out one after the other, or sequentially, simply by means of a small change in the operating conditions, but without same being truly necessary, between the two reaction steps, e.g., to transfer the reaction medium to another reactor or to subject same to certain particular treatments.
• the process of the invention is indeed very simple and very convenient to carry out. This simplicity and this convenience are virtually tantamount to a process strictly comprising but a single reaction step.
• the second reaction step is carried out under atmospheric pressure, preferably in a vessel open to the atmosphere.
• heating under atmospheric pressure is equivalent to heating in the total or virtually total absence of ammonia.
• a small amount of ammonia can be present, especially due to the decomposition of the urea to at least some extent, but even in this case the ammonia readily evolves from the reaction medium under the influence of the heat.
• the reaction temperature for the second step is typically between 80° and 220° C., preferably between 110° and 190° C.
• This second reaction step is preferably carried out in the presence of water.
• the water tends to evaporate more or less rapidly, such that, in accordance with another embodiment of the invention, liquid water is continuously fed into the reaction medium and, if appropriate, the steam leaving the reaction medium is recovered and condensed.
• water is advantageously fed into the reaction medium at a rate per hour which is less than 20% by weight of the reaction medium.
• the benzoxazolone is precipitated with water which may itself be acidified; the benzoxazolone can be purified by any known means, e.g., by recrystallization or by washing with an organic solvent.
• the process of the invention is especially worthwhile because of the good results obtained, both as regards the degree of conversion of the ortho-chlorophenol and the yields of benzoxazolone, and also in respect of the simplicity and the convenience with which the process is carried out.
• the autoclave was purged with ammonia.
• the reaction mixture was heated to 170° C. and then placed under a head of constant pressure of 22 bars of ammonia (relative pressure). Heating was continued for 6 hours, during which time NH 3 (69 g) was consumed.
• the autoclave was cooled to 110° C., degassed and fitted with a descending condenser connected to the reactor via a bent tube. The temperature was raised to 125° C.; the pressure being equal to atmospheric pressure because the reaction medium was exposed to the ambient atmosphere by means of the descending condenser. Water was added to the reaction medium at a rate of 65 cc/hour, while at the same time heating distillation were conducted for two hours at 140° C., and then for two hours at 150° C.
• the autoclave was cooled to 120° C. and water (0.8 liter) was added.
• the benzoxazolone precipitated; the reaction medium was stirred overnight and an aqueous solution of sulfuric acid containing 3 mols/liter (0.15 liter was then added.
• the benzoxazolone was filtered off and then washed and recrystallized.
• the benzoxazolone was thus obtained in a Y of 74.5% and a DC of 94.5%.
• Example 1 was repeated, but with 9.9 g of Cu 2 Cl 2 (instead of 19.8 g) being utilized. 60 g of NH 3 were consumed. The benzoxazolone was obtained in a Y of 79.5% and a DC of 84.5%.
• Example 1 was repeated, but the following amounts of reactants were utilized: ortho-chlorophenol (385.5 g), urea (270 g) and Cu 2 Cl 2 (29.7 g).
• the autoclave was heated at 170° C. for 8 hours; the pressure initially stabilized at 26 bars and then gradually decreased to 10 bars upon completion of the reaction.
• the autoclave was cooled to 120° C. and degassed, and then water (30 g) was slowly introduced therein and the autoclave heated for two hours at 140° C., and then for two hours at 150° C., while at the same time distilling the reaction mixture at atmospheric pressure.
• the benzoxazolone was obtained in a Y of 70% and a DC of 96%.
• Example 4 was repeated, but 9.9 g of Cu 2 Cl 2 (instead of 19.8 g) were utilized; the benzoxazolone was thus obtained in a Y of 70.5% and a DC of 80.5%.
• the autoclave was sealed and purged with NH 3 , and NH 3 (51 g) was introduced.
• the autoclave was heated at 170° C. for 8 hours.
• the pressure initially stabilized at 38 bars (relative pressure) and then gradually decreased to 24 bars upon completion of the reaction.
• the autoclave was cooled and opened; water (16 g) was added and the resulting mixture was heated, in the ambient air and under atmospheric pressure, at about 135° C. for 4 hours.
• the autoclave was heated for 8 hours at 140° C. The initial pressure of 32 bars gradually decreased to 17 bars.
• the autoclave was cooled to 125° C., water (2 cc) was added, and then, without any distillation, the autoclave was heated to atmospheric pressure for 1 hour at 130° C. and for 2 hours at 150° C.
• the benzoxazolone was obtained in a Y of 46% and a DC of 95.5%.
• Example 7 The autoclave was heated for 8 hours at 170° C. The pressure stabilized at 10 bars and gradually declined to 9 bars. The procedure was then continued exactly as in Example 7 and the benzoxazolone was obtained in a Y of 41.5% and a DC of 89%.
• the autoclave was purged with nitrogen and heated for 8 hours at 170° C.
• the pressurized ammonia atmosphere was thus obtained by decomposition of the urea in the presence of water. Such pressure stabilized at 40 bars, and remained constant at this value.
• the autoclave was cooled, degassed and heated for 2 hours at 130° C. and then for 2 hours at 150° C., while at the same time conducting the distillation at atmospheric pressure.
• the benzoxazolone was obtained in a Y of 57.5% and a DC of 95%.
• the autoclave was sealed and purged with NH 3 , and heated at 170° C., for 6 hours.
• the pressure initially stabilized at about 26 bars (relative pressure) and then gradually declined to about 10 bars upon completion of the reaction.
• the autoclave was cooled to 120° C. and opened and the contents of the autoclave were transferred into a 250 cc round-bottomed flask under atmospheric pressure, the flask being equipped with a distillation system similar to that described in Example 1.
• Water (3 cc) was added slowly to this flask; the mixture was subsequently heated for 2 hours at 140° C. and then for 2 hours at 150° C., water being added uniformly at the rate of 4.5 cc/hour throughout the distillation.
• Benzoxazolone was likewise obtained in the presence of FeCl 2 , NiCl 2 and Ni.
• the autoclave was heated for 6 hours at 210° C.
• the pressure initially stabilized at about 24 bars (relative pressure) and then gradually declined to about 10 bars upon completion of the reaction.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Heterocyclic Carbon Compounds Containing A Hetero Ring Having Nitrogen And Oxygen As The Only Ring Hetero Atoms (AREA)
• Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
• Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

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Citations (3)

• 1979
  • 1979-05-08 FR FR7912139A patent/FR2456094A1/fr active Granted
• 1980
  • 1980-03-13 IL IL59609A patent/IL59609A/xx unknown
  • 1980-04-25 US US06/143,857 patent/US4309549A/en not_active Expired - Lifetime
  • 1980-04-25 SU SU802912761A patent/SU1132790A3/ru active
  • 1980-05-01 GB GB8014440A patent/GB2048879B/en not_active Expired
  • 1980-05-06 IE IE924/80A patent/IE49784B1/en unknown
  • 1980-05-06 ZA ZA00802717A patent/ZA802717B/xx unknown
  • 1980-05-06 PT PT71191A patent/PT71191B/pt unknown
  • 1980-05-06 BR BR8002790A patent/BR8002790A/pt unknown
  • 1980-05-06 DK DK197580A patent/DK151333C/da not_active IP Right Cessation
  • 1980-05-06 CA CA000351332A patent/CA1150275A/en not_active Expired
  • 1980-05-06 JP JP6045780A patent/JPS5625172A/ja active Granted
  • 1980-05-07 EP EP80420052A patent/EP0018931B1/fr not_active Expired
  • 1980-05-07 AT AT80420052T patent/ATE22076T1/de active
  • 1980-05-07 ES ES491226A patent/ES491226A0/es active Granted
  • 1980-05-07 HU HU801118A patent/HU185217B/hu unknown
  • 1980-05-07 DE DE8080420052T patent/DE3071747D1/de not_active Expired

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